An embarrassing split between President Nicolas Sarkozy and his prime minister, François Fillon, emerged on Tuesday over how to deal with the threat from France's far-Right National Front.

Marine Le Pen's National Front (FN) made historic gains in the first round of local elections on Sunday, only trailing Mr Sarkozy's UMP party by two percentage points on 15pc.

The Socialists, who came top on 25pc, are calling for a "Republic front" against the FN in next Sunday's second round, where the far-Right is present in almost 400 "cantons" in the country's 100 departments. The Left is urging its supporters to vote UMP in cantons where it is an also-ran to keep the FN out.

Several UMP moderates called on its electorate to vote tactically. But Mr Sarkozy refused to explicitly urge his supporters to vote for the Left in the 200 or so cantons where the race is between Socialists and the FN. He told party leaders that a call to vote Socialist "would be tantamount to sending a signal of collusion between the UMP and Socialist Party".

However, on Monday night, prime minister Fillon, who has reportedly been ill at ease with attempts by Mr Sarkozy to veer Right to attract FN support, caused confusion by telling UMP members: "You must vote against the National Front".

On Tuesday, Bernard Debré, a UMP MP, said the message from the top was disastrous. "The split at the head of state is catastrophic. I don't understand François Fillon's position," he said.

Dominique Paillé, a former UMP spokesman, said: "We must take care not to fuel the creation within the ruling party of a pole that clearly urges blocking the FN and another more ambiguous (stance)."

The Left pounced on the mixed message, saying it showed the president was prepared to compromise the values of the French Republic and pander to the FN at the risk of sparking civil war within his own party. François Hollande, a Socialist presidential hopeful, denounced a "grave difference of opinion" between the president and prime minister. "It would be logical if they split up," he said.

In a belated damage limitation exercise, Mr Fillon announced that there was "no difference" between his view and that of Mr Sarkozy. "For the President, the choice (for voters) is either to abstain or to vote Socialist," he said.

Jean-Marie Le Pen, whose daughter succeeded him as FN leader in January, relished the row, saying the confusion was proof of "panic on the bridge" between the government's "admiral and commander-in-chief".